Front: 18*8.5 235/40
Rear: 18*10 315/30

 

Why on earth would you want it like that? You would have some very nice understeer.

 

You would want 8" rims for the 235/40 and 11" rims for the 315/30 if you were so inclined to put that setup on your car. You would very likely have problems with VDC and you would have to roll the fenders on the rear of the car.